Frits and obscuration enamels for automotive applications

Abstract

Frits, obscuration enamel compositions including frits and automotive windshields having obscuration enamel compositions applied thereto are described. According to one or more embodiments, the obscuration enamel composition comprises a paste component and a frit component having Bi 2 O 3 , SiO 2 and B 2 O 3 and being substantially free of Na 2 O. In other embodiments, a reducing agent is included in the frit component. Obscuration enamels of some embodiments have a total solids content of at least 80% by weight.

1. An obscuration enamel composition comprising:
 a paste component; and 
 a frit component comprising
 Bi 2 O 3  in an amount in the range of about 20% to about 60% by weight; 
 SiO 2  in an amount in the range of about 15% to about 30% by weight; 
 B 2 O 3  in an amount in the range of from about 2% to about 9% by weight; and 
 
 two or more oxides selected from SrO, BaO and ZnO in an amount greater than about 8.95% by weight, 
 wherein the composition is substantially free of Na 2 O and the frit component comprises about 0% by weight TiO 2 . 
 
     
     
       2. The obscuration enamel composition of  claim 1 , wherein the frit component has a particle size of D90 in the range of about 4 μm to about 12 μm. 
     
     
       3. The obscuration enamel composition of  claim 1  further comprising one or more nucleating agents. 
     
     
       4. The obscuration enamel composition of  claim 3 , wherein the nucleating agents are selected from a group consisting of bismuth silicate, titania, zinc aluminate and combinations thereof. 
     
     
       5. The obscuration enamel composition of  claim 4 , wherein the frit component further comprises Na 2 O in an amount less than about 0.2% by weight and the paste component is substantially free of added silicon metal powder. 
     
     
       6. The obscuration enamel composition of  claim 5 , wherein the frit component comprises one or more reducing agents smelted therein. 
     
     
       7. The obscuration enamel composition of  claim 5 , wherein the frit component comprises:
 Bi 2 O 3  in an amount in the range of about 40% to about 50% by weight; 
 SiO 2  in an amount in the range of about 20% to about 30% by weight; and 
 B 2 O 3  in an amount in the range of about 2% to about 5% by weight. 
 
     
     
       8. The obscuration enamel composition of  claim 7 , wherein the frit component further comprises at least one member selected from the group consisting of:
 K 2 O in an amount in the range of about 0% to about 7% by weight; 
 Li 2 O in an amount in the range of about 0% to about 7% by weight; 
 CuO in an amount in the range of about 0% to about 5% by weight; 
 La 2 O 3  in an amount in the range of about 0% to about 10% by weight; 
 Al 2 O 3  in an amount in the range of about 0% to about 4% by weight, and 
 fluoride in an amount in the range of 0% to about 4% by weight. 
 
     
     
       9. The obscuration enamel composition of  claim 8  having total solids content in an amount greater than about 80% by weight. 
     
     
       10. An automotive glass comprising the obscuration enamel composition of  claim 1  disposed on a surface of the glass. 
     
     
       11. An automotive glass comprising the obscuration enamel composition of  claim 3  disposed on a surface of the glass. 
     
     
       12. An obscuration enamel composition comprising:
 a paste component; and 
 a frit component comprising
 Bi 2 O 3  in an amount in the range of about 20% to about 60% by weight; 
 SiO 2  in an amount in the range of about 20% to about 26% by weight; and 
 B 2 O 3  in an amount in the range of about 2% to about 5% by weight; and 
 two or more oxides selected from SrO, BaO and ZnO; 
 
 wherein the composition has a solids content over 85% by weight and is substantially free of Na 2 O and the frit component comprises about 0% by weight TiO 2 . 
 
     
     
       13. The obscuration enamel composition of  claim 12  further comprising one or more nucleating agents. 
     
     
       14. The obscuration enamel composition of  claim 13 , wherein the one or more nucleating agents are selected from a group consisting of bismuth silicate, titania, zinc aluminate and combinations thereof. 
     
     
       15. The obscuration enamel composition of  claim 14 , wherein the frit component further comprises Na 2 O in an amount less than about 0.2% by weight and the paste component is substantially free of added silicon metal powder. 
     
     
       16. The obscuration enamel composition of  claim 15 , wherein the frit component comprises one or more reducing agents smelted therein. 
     
     
       17. The obscuration enamel composition of  claim 15 , wherein the frit component further comprises at least one member selected from the group consisting of:
 K 2 O in an amount in the range of about 0% to about 7% by weight; 
 Li 2 O in an amount in the range of about 0% to about 7% by weight; 
 CuO in an amount in the range of about 0% to about 5% by weight; 
 La 2 O 3  in an amount in the range of about 0% to about 10% by weight; 
 Al 2 O 3  in an amount in the range of about 0% to about 4% by weight; and 
 fluoride in an amount in the range of 0% to about 4% by weight. 
 
     
     
       18. The obscuration enamel composition of  claim 12 , wherein the frit component has a particle size of D90 in the range of about 4 μm to about 12 μm. 
     
     
       19. An automotive glass comprising the obscuration enamel composition of  claim 12  disposed on a surface of the glass. 
     
     
       20. An automotive glass comprising the obscuration enamel composition of  claim 13  disposed on a surface of the glass.